These shell scripts and associated control files may be used to
create a customized regime of administration and management for
Performance Co-Pilot (see PCPintro(1)) archive log files.
pmlogger_daily is intended to be run once per day, preferably in the
early morning, as soon after midnight as practicable. Its task is to
aggregate, rotate and perform general housekeeping one or more sets
of PCP archives.
After some period, old PCP archives are discarded. This period is 14
days by default, but may be changed using the -k option. Some
special values are recognized for the period (discard), namely 0 to
keep no archives beyond the current one, and forever or never to
prevent any archives being discarded. Note that the semantics of
discard are that it is measured from the time of last modification of
each archive, and not from the current day. This has subtle
implications for compression (see below) - the compression process
results in the creation of new archive files which have new
modification times. In this case, the discard period (re)starts from
the time of compression.
Archive data files can optionally be compressed after some period to
conserve disk space. This is particularly useful for large numbers
of pmlogger processes under the control of pmlogger_check. If
transparent_decompress is enabled when libpcp was built (can be
checked with pmconfig -L), then the default behaviour is compression
``as soon as possible'' otherwise the default behaviour is to not
compress files (which matches the historical default behaviour in
earlier PCP releases).
The -x option controls compression and compress specifies the number
of days after which to compress archive data files and metadata
files. If compress is 0 then compression will be applied as soon as
possible. If compress is never or forever then no compression will
be done. The environment variable PCP_COMPRESSAFTER may be used as
an alternative mechanism to define compress. If both
PCP_COMPRESSAFTER and -x specify different values for compress then
the environment variable value is used and a warning is issued.
The -X option specifies the program to use for compression - by
default this is xz(1). The environment variable PCP_COMPRESS may be
used as an alternative mechanism to define program. If both
PCP_COMPRESS and -X specify different compression programs then the
environment variable value is used and a warning is issued.
Use of the -Y option allows a regular expression to be specified
causing files in the set of files matched for compression to be
omitted - this allows only the data file to be compressed, and also
prevents the program from attempting to compress it more than once.
The default regex is ".(index|Z|gz|bz2|zip|xz|lzma|lzo|lz4)$" - such
files are filtered using the -v option to egrep(1). The environment
variable PCP_COMPRESSREGEX may be used as an alternative mechanism to
define regex. If both PCP_COMPRESSREGEX and -Y specify different
values for regex then the environment variable value is used and a
warning is issued.
To accommodate the evolution of PMDAs and changes in production
logging environments, pmlogger_daily is integrated with
pmlogrewrite(1) to allow optional and automatic rewriting of archives
before merging. If there are global rewriting rules to be applied
across all archives mentioned in the control file(s), then create the
directory $PCP_SYSCONF_DIR/pmlogrewrite and place any pmlogrewrite(1)
rewriting rules in this directory. For rewriting rules that are
specific to only one family of archives, use the directory name from
the control file(s) - i.e. the fourth field - and create a file, or a
directory, or a symbolic link named pmlogrewrite within this
directory and place the required rewriting rule(s) in the
pmlogrewrite file or in files within the pmlogrewrite subdirectory.
pmlogger_daily will choose rewriting rules from the archive directory
if they exist, else rewriting rules from
$PCP_SYSCONF_DIR/pmlogrewrite if that directory exists, else no
rewriting is attempted.
The -r command line option acts as an over-ride and prevents all
archive rewriting with pmlogrewrite(1) independent of the presence of
any rewriting rule files or directories.
Sometimes PMDA changes require all archives to be rewritten, not just
the ones involved in any current merging. This is required for
example after a PCP upgrade where a new version of an existing PMDA
has revised metadata. The -R command line forces this universal-
style of rewriting.
The -R option to pmlogger_daily is mutually exclusive with both the
-r and -M options.
As an alternate mechanism, if the file
$PCP_LOG_DIR/pmlogger/.NeedRewrite exists when pmlogger_daily starts
then this is treated the same as specifying -R on the command line
and $PCP_LOG_DIR/pmlogger/.NeedRewrite will be removed once all the
rewriting has been done.
By default all possible archives will be merged. The -o option
reinstates the old behaviour in which only yesterday's archives will
be considered as merge candidates.
In the special case where only a single input archive needs to be
merged, pmlogmv(1) is used to rename the archive, otherwise
pmlogger_merge(1) is used to merge all of the archives for a single
host and a single day into a new PCP archive and the individual
archives are removed.
The -M option may be used to disable archive merging (or renaming)
and rewriting (-M implies -r). This is most useful in cases where
the archives are being incrementally copied to a remote repository,
e.g. using rsync(1). Merging, renaming and rewriting all risk an
increase in the synchronization load, especially immediately after
pmlogger_daily has run, so -M may be useful in these cases.
To assist with debugging or diagnosing intermittent failures the -t
option may be used. This will turn on very verbose tracing (-VV) and
capture the trace output in a file named
$PCP_LOG_DIR/pmlogger/daily.datestamp.trace, where datestamp is the
time pmlogger_daily was run in the format YYYYMMDD.HH.MM. In
addition, the want argument will ensure that trace files created with
-t will be kept for want days and then discarded.
In addition, if the PCP ``notices'' file ($PCP_LOG_DIR/NOTICES) is
larger than 20480 bytes, pmlogger_daily will rename the file with a
``.old'' suffix, and start a new ``notices'' file. The rotate
threshold may be changed from 20480 to size bytes using the -s
option.
Use of the -m option causes pmlogger_daily to construct a summary of
the ``notices'' file entries which were generated in the last 24
hours, and e-mail that summary to the set of space-separated
addresses. This daily summary is stored in the file
$PCP_LOG_DIR/NOTICES.daily, which will be empty when no new
``notices'' entries were made in the previous 24 hour period.
If the -K option is specified for pmlogger_daily then only the
compression tasks are attempted, so no pmlogger(1) rotation, no
culling, no rewriting, etc. When -K is used and a compress value of
0 is in effect (from -x on the command line or PCP_COMPRESSAFTER in
the environment or via the control file) this is intended for
environments where compression of archives is desired before the
scheduled daily processing happens. To achieve this, once
pmlogger_check has completed regular processing, it calls
pmlogger_daily with just the -K option. Provided PCP_COMPRESSAFTER
is set to 0 along with any other required compression options to
match the scheduled invocation of pmlogger_daily, then this will
compress all volumes except the ones being currently written by
pmlogger(1).
If the -p option is specified for pmlogger_daily then the status of
the daily processing is polled and if the daily pmlogger(1) rotation,
culling, rewriting, compressing, etc. has not been done in the last
24 hours then it is done now. The intent is to have pmlogger_daily
called regularly with the -p option (at 30 mins past the hour, every
hour in the default cron(8) set up) to ensure daily processing
happens as soon as possible if it was missed at the regularly
scheduled time (which is 00:10 by default), e.g. if the system was
down or suspended at that time.
With the -p option, pmlogger_daily simply exits if the previous day's
processing has already been done.
The -K and -p options to pmlogger_daily are mutually exclusive.
The script $PCP_BINADM_DIR/pmlogger_daily could be copied and
modified to implement a site-specific procedure for end-of-week
and/or end-of-month management for a set of PCP archives.
pmlogger_check may be run at any time, and is intended to check that
the desired set of pmlogger(1) processes are running, and if not to
re-launch any failed loggers. Use of the -s option provides the
reverse functionality, allowing the set of pmlogger processes to be
cleanly shutdown. Use of the -C option queries the system service
runlevel information for pmlogger, and uses that to determine whether
to start processes.
The -T option provides a terser form of output for pmlogger_check
that is most suitable for a pmlogger ``farm'' where many instances of
pmlogger are expected to be running.
Using -N option invokes the scripts in a ``show me'' or ``dry run''
mode where the tasks that would be performed are reported, but no
changes are made. This is typically used for debugging in
combination with one (verbose) or two (very verbose) -V options.
Both pmlogger_daily and pmlogger_check are controlled by PCP logger
control file(s) that specifies the pmlogger instances to be managed.
The default control file is $PCP_PMLOGGERCONTROL_PATH, but an
alternate may be specified using the -c option. If the directory
$PCP_PMLOGGERCONTROL_PATH.d (or control.d from the -c option) exists,
then the contents of any additional control files therein will be
appended to the main control file (which must exist).
Warning: The $PCP_PMLOGGERCONTROL_PATH and
$PCP_PMLOGGERCONTROL_PATH.d files must not be writable by any user
other than root.
The control file(s) should be customized according to the following
rules that define for the current version (1.1) of the control file
format.
1. Lines beginning with a ``#'' are comments.
2. Lines beginning with a ``$'' are assumed to be assignments to
environment variables in the style of sh(1), and all text
following the ``$'' will be eval'ed by the script reading the
control file, and the corresponding variable exported into the
environment. This is particularly useful to set and export
variables into the environment of the administrative scripts,
e.g.
$ PMCD_CONNECT_TIMEOUT=20
3. There must be a version line in the initial control file of the
form:
$ version=1.1
4. There should be one line in the control file(s) for each pmlogger
instance of the form:
hosty|n y|n directory args
5. Fields within a line of the control file(s) are usually separated
by one or more spaces or tabs (although refer to the description
of the directory field for some important exceptions).
6. The first field is the name of the host that is the source of the
performance metrics for this pmlogger instance.
7. The second field indicates if this is a primarypmlogger instance
(y) or not (n). Since the primary logger must run on the local
host, and there may be at most one primary logger for a
particular host, this field can be y for at most one pmlogger
instance, in which case the host name must be the name of the
local host.
8. The third field indicates if this pmlogger instance needs to be
started under the control of pmsocks(1) to connect to a pmcd
through a firewall (y or n).
9. The fourth field is a directory name. All files associated with
this pmlogger instance will be created in this directory, and
this will be the current directory for the execution of any
programs required in the maintenance of those archives. A useful
convention is that primary logger archives for the local host
with hostname myhost are maintained in the directory
$PCP_LOG_DIR/pmlogger/myhost (this is where the default pmlogger
start-up script in $PCP_RC_DIR/pcp will create the archives),
while archives for the remote host mumble are maintained in
$PCP_LOG_DIR/pmlogger/mumble.
10. The directory field may contain embedded shell syntax that will
be evaluated by sh(1) to produce the real directory name to be
used. The allowed constructs are:
· Any text (including white space) enclosed with $( and ).
· Any text (including white space) enclosed with ` and ` (back
quotes).
· Any text (including white space) enclosed with " and " (double
quotes).
· Any word containing a $ (assumed to introduce an environment
variable name).
11. All other fields are interpreted as arguments to be passed to
pmlogger(1) and/or pmnewlog(1). Most typically this would be the
-c option.
The following sample control lines specify a primary logger on the
local host (bozo), and non-primary loggers to collect and log
performance metrics from the hosts wobbly and boing.
$version=1.1
bozo y n $PCP_LOG_DIR/pmlogger/bozo -c config.default
wobbly n n "/store/wobbly/$(date +%Y)" -c ./wobbly.config
boing n n $PCP_LOG_DIR/pmlogger/boing -c ./pmlogger.config
Typical crontab(5) entries for periodic execution of pmlogger_daily
and pmlogger_check are given in $PCP_SYSCONF_DIR/pmlogger/crontab
(unless installed by default in /etc/cron.d already) and shown below.
# daily processing of archive logs
14 0 * * * $PCP_BINADM_DIR/pmlogger_daily
# every 30 minutes, check pmlogger instances are running
25,55 * * * * $PCP_BINADM_DIR/pmlogger_check
In order to ensure that mail is not unintentionally sent when these
scripts are run from cron(8) diagnostics are always sent to a log
file. By default, this file is
$PCP_LOG_DIR/pmlogger/pmlogger_daily.log or
$PCP_LOG_DIR/pmlogger/pmlogger_check.log but this can be changed
using the -l option. If this log file already exists when the script
starts, it will be renamed with a .prev suffix (overwriting any log
file saved earlier) before diagnostics are generated to the log file.
The -l and -t options cannot be used together.
The output from the cron execution of the scripts may be extended
using the -V option to the scripts which will enable verbose tracing
of their activity. By default the scripts generate no output unless
some error or warning condition is encountered.

$PCP_PMLOGGERCONTROL_PATH
the PCP logger control file
Warning: this file must not be writable by any user other
than root.
$PCP_PMLOGGERCONTROL_PATH.d
optional directory containing additional PCP logger control
files, typically one per host
Warning: the files herein must not be writable by any user
other than root.
$PCP_SYSCONF_DIR/pmlogger/crontab
sample crontab for automated script execution by $PCP_USER
(or root). Exists only if the platform does not support
the /etc/cron.d mechanism.
$PCP_VAR_DIR/config/pmlogger/config.default
default pmlogger configuration file location for the local
primary logger, typically generated automatically by
pmlogconf(1).
$PCP_LOG_DIR/pmlogger/hostname
default location for archives of performance information
collected from the host hostname$PCP_LOG_DIR/pmlogger/hostname/lock
transient lock file to guarantee mutual exclusion during
pmlogger administration for the host hostname - if present,
can be safely removed if neither pmlogger_daily nor
pmlogger_check are running
$PCP_LOG_DIR/pmlogger/hostname/Latest
PCP archive folio created by mkaf(1) for the most recently
launched archive containing performance metrics from the
host hostname$PCP_LOG_DIR/NOTICES
PCP ``notices'' file used by pmie(1) and friends
$PCP_LOG_DIR/pmlogger/pmlogger_check.log
if the previous execution of pmlogger_check produced any
output it is saved here. The normal case is no output in
which case the file does not exist.
$PCP_LOG_DIR/pmlogger/pmlogger_daily.log
if the previous execution of pmlogger_daily produced any
output it is saved here. The normal case is no output in
which case the file does not exist.
$PCP_LOG_DIR/pmlogger/hostname/SaveLogs
if this directory exists, then the log file from the -l
argument of a newly launched pmlogger(1) for hostname will
be linked into this directory with the name archive.log
where archive is the basename of the associated pmlogger(1)
PCP archive files. This allows the log file to be
inspected at a later time, even if several pmlogger(1)
instances for hostname have been launched in the interim.
Because the cron-driven PCP archive management scripts run
under the uid of the user ``pcp'',
$PCP_LOG_DIR/pmlogger/hostname/SaveLogs typically needs to
be owned by the user ``pcp''.
$PCP_LOG_DIR/pmlogger/.NeedRewrite
if this file exists, then this is treated as equivalent to
using -R on the command line and the file will be removed
once all rewriting has been done.

Environment variables with the prefix PCP_ are used to parameterize
the file and directory names used by PCP. On each installation, the
file /etc/pcp.conf contains the local values for these variables.
The $PCP_CONF variable may be used to specify an alternative
configuration file, as described in pcp.conf(5).
The default behaviour, when pmlogger(1) configuration comes from
pmlogconf(1), is to regenerate the configuration file and check for
changes whenever pmlogger(1) is started from pmlogger_check. If the
PMDA configuration is stable, this is not necessary, and setting
$PMLOGGER_CHECK_SKIP_LOGCONF to yes disables the regeneration and
checking.

This page is part of the PCP (Performance Co-Pilot) project.
Information about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
pcp@groups.io. This page was obtained from the project's upstream
Git repository ⟨https://github.com/performancecopilot/pcp.git⟩ on
2019-05-09. (At that time, the date of the most recent commit that
was found in the repository was 2019-05-08.) If you discover any
rendering problems in this HTML version of the page, or you believe
there is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Performance Co-Pilot PCP PMLOGGER_CHECK(1)